﻿Public Class MachDon
    Inherits MachDien

    Private _r As Double

    Public Sub New(ByVal r As Double)
        _r = r
    End Sub

    Public Overrides Sub Nhap()
        Console.Write("Nhap r:")
        _r = Console.ReadLine()
    End Sub

    Public Overrides Sub Xuat()
        'cai dat sau
    End Sub

    Public Overrides Function TongTro() As Double
        Dim kq As Double
        kq = _r
        Return kq
    End Function
End Class
